There are numerous applications where it is desirable to use two or more pumps on a cyclical basis for maintaining the level of fluid in a sump or a tank. The use of multiple pumps increases overall system reliability and extends the time period during which any one pump may be kept in service.
Prior products are known for the purpose of cyclically energizing the members of a group of pumps. One common use involves pump alternator circuitry in combination with two pumps for maintaining the level of fluid in a sump or a tank.
Such systems usually require some form of feedback so as to determine when to energize a selected pump. At times, feedback is also used to determine when to terminate energizing of that pump.
Some of the known pump alternator systems use current sensors in the feedback path to determine when a pump should be energized. Such sensors tend to be more expensive than desired in many types of products.
There thus continues to be a need for cost effective, reliable pump alternator systems. Preferably, such systems would incorporate relatively inexpensive feedback elements and could be expandable to more than two pumps. Also, it would be preferred if standard, off-the-shelf, pumps could be used.